Method of making bifocal lenses.



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Patented Oct. 20, 1908.

UNITED STATES PATENT OFFICE.

j Ail-STEVENS, OF PRovInENon;nHoDnisLANn.

'5 .1 amazon or, MAKING niliooanmnsns.

- Specification of Letters Eatent.

Patented Oct. so, 1908.

Application filed February s, 1903:. Serial No. 416,622.

To all whomit may concern} 1 Beit known thatI, LOUIS WYILHELM, a

. citizen of the United States, residing at Worcester, in the county of Worcester and State of Massachusetts, have invented certam new and useful Improvements in Methods oflMaking Bifocal Lenses, of which the I following is a specification.

My invention relates tobi-focal lenses wherein twocomponent le'ns pieces or blanks are united into a composite. or unitary -whole by fusing, and has for its essential objects the avoidance of scratching the said blanks duringthe progress of construction whereby the visual field is married; to avoi lmperfect-ions resultant upon the formation .g bubbles intermediate I the contiguous lgbl ank surfii'cesfdiiring the'weldi'ng action; to

accomplishthe fusion by means which shall not su'bjeCtf' t-he component lens parts to danger of fractur Hn'grmding the final prodnot; to insult inst dislocation or derangement of the component blanks during fusion; and to reduce the expense of the fusing operation. My invention consists, therefore, in the process or method of uniting the main and auxiliary lens blanks hereinafter set forth and claimed.

In the drawings, which constitute a part of this specification, Figure 1 is a plan view of a lens blank after the molding operation. Fig. 2, a like view of the auxiliary blank. Fig. 8, a section of the main blank -online as w of Fig. 1, showing in section the auxiliary blank in position for fusingL' Fig. 4, a like section of the parts after fusing. Fig. 5, a similar section of the same after grind- .ing. Fig. 6, a plan of the completed lens. Fi'g.'7, a sectional view of. a modified form of lens parts preparatory to-fusing, and Fig.

8, a plan view of a second modified form of the main lens blank.

Like reference characters indicate like parts throughout the views.

In detail my process conslsts in molding cavity, C, intermediate the projections, upon its face.

In this instance, the' projections The surface of the The are three in number. cavity, O, is smoothed by gr1nd1ng.

' projections are adjacent the margin-off the in blank, A. To the parts thus assembled,

convenient means. The projections separate the lower surface of the blank, D, from the surface of the cavity, C, until the blank, D, becomes plastic, sinks into the cavity, C, and becomes fused sufliciently to become perfectly welded with the blank, A, as shown in Fig. 4E. The portions of the blank, D, which extend above the blank, A, and the projections, B, are next ground away, and the sur face of the completed lens polished. If preferred, the projections may be shouldered or irregular, B, as shown in Fig. 7, adapted to form a seat for the auxiliary lens. in Fig. 8, the projections, B are of arcuate form. It is, however, essential that the projections under all circumstances be integral with the blank, A.

What I claim is,

1. The method of making bi-focal lenses which consists in molding glass to form a blank with integral projections and a cavity upon its surface, placing a fusible disk upon the projections, and subjecting the parts to a welding heat to unite disk and blank.

2. The method of making bi-focal lenses which consists in molding glass to form a blank with circularly disposed integral projections upon its surface and a cavity in the surface of the blank within and concentric to the projections, )lacing a disk upon the prowith the blank.

3. The method of making bi-focal lenses which consists in molding glass to form a blank with integral projections upon its sur face, forming a cavity in the surface of the blank within and concentric to the projections, placing a disk upon the projections, submitting the assembled parts to heat to precipitate the disk into the cavity and adhere to the blank, and grinding and polishing the completed lens.

i. The method of making bifocal lenses which consists in molding a blank with a heat is applied in a mufiie or by any other jections, and su mitting tlie whole to heat whereby thedisk sinks upon and is united ezivi'ty and integral projections areund the projections, and subjecting the parts to a 10, cavity, next grinding out the cavity, then welding heat to unite the disk and blank.

gm! projectiens upon its surface, grinding a cavity in the surface of the blank within the placing awfusible disk upon the projections, In testimony whereof I have afiixwi my and finally subjecting the parts to a welding signature in presence of two witnesses. heat to unite the parts. i 1 ,7 i

5. The method of making oi-focal lenses LOUIb which consists in moldinga blank with inte- Witnesses:

HORATIQ E. BELLoWs,

JOSEPH C. BURNS. 

